For spatially overlapping \(^{87}\) Rb and \(^{129}\) Xe spins, their Fermi-contact interaction introduces an effective field \(\lambda M^{n} \textbf {P}^{n}\)  on \(^{87}\) Rb spins generated by \(^{129}\) Xe nuclear magnetization [1]}. Such an effective field can be described by
\(\textbf {B}_{\rm {eff}}=\lambda M^{n} \textbf {P}^{n}=\frac{8\pi }{3} \kappa _0 M^{n} \textbf {P}^{n},\) 
